Convert string16 to base::string16 in content.

content/browser/indexed_db/indexed_db_backing_store_unittest.cc

Index: content/browser/indexed_db/indexed_db_backing_store_unittest.cc
diff --git a/content/browser/indexed_db/indexed_db_backing_store_unittest.cc b/content/browser/indexed_db/indexed_db_backing_store_unittest.cc
index 396189e51955a6c5797e269eab41a35ab77809d8..d3e82964af4498d251d0c5be1aa3c386ab9171eb 100644
--- a/content/browser/indexed_db/indexed_db_backing_store_unittest.cc
+++ b/content/browser/indexed_db/indexed_db_backing_store_unittest.cc
@@ -236,19 +236,19 @@ TEST_F(IndexedDBBackingStoreTest, InvalidIds) {
 }
 
 TEST_F(IndexedDBBackingStoreTest, CreateDatabase) {
-  const string16 database_name(ASCIIToUTF16("db1"));
+  const base::string16 database_name(ASCIIToUTF16("db1"));
   int64 database_id;
-  const string16 version(ASCIIToUTF16("old_string_version"));
+  const base::string16 version(ASCIIToUTF16("old_string_version"));
   const int64 int_version = 9;
 
   const int64 object_store_id = 99;
-  const string16 object_store_name(ASCIIToUTF16("object_store1"));
+  const base::string16 object_store_name(ASCIIToUTF16("object_store1"));
   const bool auto_increment = true;
   const IndexedDBKeyPath object_store_key_path(
       ASCIIToUTF16("object_store_key"));
 
   const int64 index_id = 999;
-  const string16 index_name(ASCIIToUTF16("index1"));
+  const base::string16 index_name(ASCIIToUTF16("index1"));
   const bool unique = true;
   const bool multi_entry = true;
   const IndexedDBKeyPath index_key_path(ASCIIToUTF16("index_key"));